Electromagnetic device



1,603,873 H. K. SANDELL I ELECTROMAGNETIC DEVICE Oct. 19 1926.

Ori inal Filed June 14, 1922 2 Sheets-Sheet 1 Oct, 19,1926. 1,603,873

H. K. SANDELL ELECTROMAGNETIC DEVICE Original Filed June 14. 1922 2 Sheet s-'-S l1eet 2 Patented Oct. 19, 1926.

UNITED STATES 1,603,873 PATENT orrics.

HENRY K. SANDELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO MILLS NOVELTY GOM- PANY OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS.

ELECTROMAGNETIC nEvroE.

Original application filed June 14, 1922, Serial No. 568,228. Divided and this application filed October is; 1e24. Serial No. 743,282.

The present invention relates to an electromagnet device, which is particularly adapted for use in connection with piano playing devices, but which may be used in other situations. In a piano playing device, the improved electromagnet device may be usefully employed for various purposes. For example, it may be employed for the purpose or controlling the position of a ham- -mer'-rail, or it may be employed for control ling the position of a damper.- In means of the character referred to, the improved device can be most advantageously used in an embodiment in which the arma ture of one electromagnet serves to actuate and releasably hold an actuating member employed in connection with the piano action, and the armature of another electromagnet serves to interlockingly engage the firstmentioned armature and prevent its return to its initial position until the armature of thesecond-mentioned magnet is withdrawn by energizing its coil.

The present application constitutes a division of Sandell application No. 568,226,

filed June 14, 1922. The invention is illustrated in one preferred embodiment in the accompanying drawings, in which.

Fig. 1 is a broken vertical sectional view of a piano playing device, showing also the improved electromagnet device used in conjunction therewith; Fig. 2, a broken front elevational view of the mechanism shown in Fig. 1; Fig. 3, a broken sectional View showing the construction of the electromagn'et device; Fig. 4, a broken plan view of the device shown in Fig. 3; and F ig. 5, a 'diagranr matic View illustrating the manner in which the hammer-railof thepiano action is controlled bythe improved electromagnet de- VICE.

i It may be stated that in apiano action, one method of controlling expression is by limiting the range of movement of the hammer, trolling the position of the hammer-rail which limits the swing of the hammer away from the string, thus regulating the stroke of the hammer.

One useful application of the improved electromagnet device is illustrated in the drawings in which the electromagnet device is employed to control the positionor" the hammer-rail.

This may be accomplished by con-' In the construction illustrated, A represents the frame upon which are supported the strings A of the piano; B, a bracket carried by said frame, and upon which is mounted the piano action B, which is equipped wth'a hammer B and a hammerrail B C, a jack-butt of the piano action D an electromagnet for actuating the jackbutt; E, an actuating lever adapted to retract the ha1nmer-rail to the position shown in Fig. 1; and F, an electromagnet device comprising a pair of electromagnets having interlocking armatures, one of which is adapted to actuate the lever E.

The piano action illustrated is, in its general construction, well known, and need not be-dei-icribed in detail.

The hammer B is actuated through the medium of the usual mechanism by means otthe jack-butt C. The jack-butt C is actuated by a riser 1 which is carried by the movable core 2 of the electromagnet D. The magnet D may have its coil energized by an alternating current, and when energized will lift the core 2 and actuate the jack-butt C through the medium of the riser 1, thus causing the hammer to strike the string.

The hammer-rail B is equipped with arms 3 (one shown) which are mounted on pivots 3- carried by the bracket B.

The lever E has its central portion mount-- ed on a pivot 4tcarried by a member of the bracket. A spring 5 tends to draw the haminer-rail towards the strings. The upper end 1 of the lever E is disposed back of and engages a felt covered stud 6 which pro ects from the end of the hammer-rail. The lower end of the lever E bears against the end of the armature, or core, of the actuating electromagnet of the device F.

The device F compr1ses an actuatlng magnet F, and a looking or latching magnet F Magnets F and F are controlled by electric circuits, preferably carrying alternat ing current, as will be presently described. The magnet F comprises a coil 7 encircling a-tube of non-magnetic material8; a lami nated iron frame 9 forming a magnetic circuit about the coil, one side of the frame comprising, however, aplate 9 carried by an angle 10; and a laminated core 11 which normally occupies a retracted position, but which is adapted to be drawn into the coil 7 when the latter is energized. The core 11 gages the lower end of the lever E. Interposed between the head 12 and the end of the frame 9 is a felt washer 16. WVhen the magnet F is energized, the core 11 is drawn into the coil 7, thus moving the lever E to the position shown in Fig. 1 and thereby retracting the hammer-rail B The magnet F is disposed at right angles to the magnet F, and its armature is adapted to be projeted by means of a spring and caused to interlock with the armature of the magnet F. In this manner,'the armature of the magnet F may be held in the projected position shown in Fig. 1 until the magnet F 2 is energized.

The magnet F comprises a coil 17 through which extends a tube of nonnnagnetic ma terial 18; an iron frame 19 which extends about the coil in a longitudinal direction; a core 20 movable in the tube 18, and a spring 21 adapted to project the core to a position shown in Figs. 1 and 3. The core 20 is equipped, at its ends, with projecting stems 20 and 20 which work through bearings and 23 with which the ends of the tube 18 are fitted. The lower end of the spring 21 bears against the inner end of the bearing 23. The stem 20 is equipped with a head, or pad 24 which is adapted to interlock with the head with which the armature of the magnet F is provided, as shown in Fig. 1.

Fig. 5 illustrates the manner in which the hammer-rail B may be controlled by the magnet device F. In this figure, 25 represents a metallic track-bar, or roll, of a selfplaying piano. One main 26 of an electric circuit is connected with the member 25. The other main 2? has a branch 27 leading to one end of the magnet F and a branch 27 leading to one end of the magnet F. From the other end of the magnet F a conductor 28 leads to a contact 29 which is adapted to co-act with the. tracker-bar From the other end of the magnet F the conductor 30 leads to a contact 31 which is adapted to co act with the tracker-bar 25. Additional contacts 32 are shown, which co-act with the bar These contacts have conductors 32 which lead to the electromagnets D which serve to actuate the piano actions in a well known manner. A note sheet, or music roll, is interposed between the contacts men tioned and the tracker-bar 25, it being under stood that any one of these contacts may come into contact ith the bar 25 when a suitable slot in the note sheet permits such action.

It will be seen that the contact 31 controls the action of the magnet F. The note sheet may be provided with a series of expression-eontrolling slots co-acting with the contact 31. hen the contact 31 engages one of these slots, it closes the circuit of the magnet F, thereby causing the core 11 to be drawn into the magnet, and thus actuating the lever E and causing it to retract the ham mer-rail B so that the hammer will be permitted a greater amplitude of movement. lVhcn the armature 11 is actuated, the armature 20 is projected by the spring 21, thus causing the armature 11 to be locked, or latched, in the projected position. Thus, the hami'ner-rail will remain in retracted position until the contact 29 engages oneof a series of slots which control the action-of the magnet F In the mean time, the circuit through conductor 30 may be broken. Then the circuit is closed through the conductor 28, the magnet F is energized, and thus the armature 20 is withdrawn or retracted. This permits the lever Eto be returned to its normal position by the spring 5, the lever E, in turn, forcing the magnet 11 to the partially ejected position which it normally occupies, as shown in Fig. 3.

Vhile the magnet device has been illustrated for use in controlling expression b controlling the position of the hammer-rail: the magnet device may be employed for any similar purpose, as for example, to control the position of the-damper 34 shown in Fig. 1. The damper is connected with actuating mechanism 34 of well known construction, and a spring 35 tends to throw the damper against the strings. The. damper may be retracted through the medium of a suitable member 36. This member 36 may constitute a portion of an actuating member which is adapted to be controlled by a magnet device F of the same construction and operating in the same manner as has been illustrated with reference to the control of the hammer-rail.

It is unnecessary to illustrate and describe a duplicate ofthe magnet device F for use in controlling the action of the damper, as this will be readily understood by those skilled in the art in view of the explanation of the improved device shown in connection with the hammer-rail.

It is preferred to employ an alternating current for operating the electromagnet dethe magnet F, whose circuit is closed only for a very brief period; and that the release of the hammer-rail may be effected by means of the magnet F at any desired inst-ant by energizing the magnet F The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

\Vhat I regard as new, and desire to secure by Letters Patent, is:

1. An electromagnet device comprising a solenoid equipped at one end with a tubular guide, a non-magnetic tube within said solenoid, a magnetic core movable in said tube and equipped with a stem projecting through said guide, a head mounted on the projecting end of said stem, a second solenoid having an axis so disposed as to intercept said head when said core is in inoperative position, a non-magnetic tube extending through said second-mentioned solenoid andequipped with end caps having perforations therethrough, a magnetic core in said last-mentioned tube having rod-like extensions extending through said perforations, a head secured to one of said extensions adapted to interlockingly engage said first-mentioned head, and a spring interposed between said second-mentioned core and the opposing ca 2. An electromagnet device comprising a rectangular magnetic frame having a tubular guide extending through one end thereof, a non-magnetic tube mounted in said frame and extending through the other end thereof, a solenoid upon said non-magnetic tube, a magnetic core movable in said non-magnetic tube and equipped with a stem projecting through said guide, a head mounted on the projecting end of said stem, a cushioning pad interposed between said head and said frame; and a second electromagnet device comprising a rectangular magnetic frame having a non-magnetic tube extending through both ends of said frame and disposed at right angles to the first-mentioned non-magnetic tube, said second-mentioned non-magnetic tube being equipped with end caps provided with perforations serving as guides, a magnetic core in said second-mentioned non-magnetic tube equipped at its ends with stems working through said guides, one of said stems being equipped with a head adapted to interlock withsaid first-mentioned head, a spring confined between the core and the end cap at the opposite end of the core, and a solenoid within said second-mentioned frame encircling said second-mentioned non-magnetic tube.

3. In means of the character set forth, a rectangular frame of magneticmaterial having perforations through its end portions, a solenoid within said frame, a magnetic tube within said solenoid having its end portions projecting through said perforations and equipped with plugs provided with axial perforations, a magnetic core within said tube equipped with stems working through said last-named perforations, a coil-spring interposed between said core and one of said plugs, a head carried by the projecting end of the stem at the other end of the device, and a cushioning member interposed between said head and the adjacent plug.

HENRY K. SANDELL. 

